Apparatus and method for the production of reticulate webs



Aug. 30, 1960 P. c. WATSON ETAL 2,950,752

APPARATUS AND METHOD FOR THE PRODUCTION OF RETICULATE WEBS 2Sheets-Sheet 1 Filed Dec. 24, 1953 Aug. 30, 1960 P. c. WATSON ETAL.2,950,752

APPARATUS AND METHOD FOR THE PRODUCTION OF RETICULATE WEBS 2Sheets-Sheet 2 Filed Dec. 24, 1953 United States Patent fiice APPARATUSAND IVETHOD FOR THE PRODUC- TION F RETICULATE WEBS Paul C. Watson, NorthQuincy, and Howard 0. l VIc- Mahon, Lexington, Mass, assignors, by mesne assignments, to American Viscose Corporation, Philadelphia, Pa., acorporation of Delaware Filed Dec. 24,1953, Ser. No. 400,240

Claims. (Cl. 1541) This invention relates to fibrous bodies and moreparticularly to reticulated webs or structures formed or" fibrousmaterials and to methods and apparatus for prepan'ng such bodies orstructures.

Fibrous bodies or structures of fiber-forming organic substances aregenerally formed from filaments prepared by either extruding thefiber-forming organic substance through an orifice or by spraying theorganic substance by the use of spray guns and the like. Methods whichinvolve the extrusion of the fiber'forming substance through orificesare limited to the use of certain substances which may be filtered andwhich possess certain other characteristim, including Wet and drytensile strengths, necessary for the spinning operations. The filamentsproduced by conventional extrusion methods are continuous filaments andthe size or denier is limited by the extrusion characteristics of thesubstances or of the spinning solutions of the particular substance. Inmany instances, it is desirable to incorporate various solid materials,such as fillers, into the fibers or filaments. However, it is notpractical to do so when the material is to be extruded through fineorifices and the amount of foreign material which may be incorporated inthe fiber or filament is strictly limited. In the production of sheetmaterial or padding from such filamentary materials, it is necessary tocollect the filaments and cut them to staple lengths. The staple issubsequently processed on conventional textile and felting equipment toform a woven sheet or felted layer or'mat. Where the filament is formedof a potentially adhesive substance and it is desired to produce aproduct, with or without non-adhesive fibers, wherein the fibers arebonded together at their points of contact, it is necessary to subjectthe sheet or mat, as formed, to an activating treatment whereby thepotentially adhesive fibers become tacky or adhesive and are capable ofbonding to other fibers at their points of contact and then deactivatethe fibers.

As an alternative, fibres or filaments may be formed from a wide rangeof substances by the' use of various types of spray guns. Because of therelatively large size of the spray gun orifices as compared to extrusionorifices such as those of a rayon type spinneret, for example, thelimitations with respect to the characteristics of the spinning liquidare far less exacting than for the extrusion methods. Various materialssuch as fillers, hardening agents, plasticizing agents and the like maybe incorporated in the spinning liquids. If it is desired to form aproduct of potentially adhesive fibers and non-adhesive fibers, thepotentially adhesive fibers may be produced by spraying into an airstream containing air-borne non-adhesive fibers and collecting the mixedfibers, for example as shown in the patent to Carleton S. Francis, Jr.No. 2,357,392. 7

The general purpose of the present invention is to provide a method andapparatus for the preparation of Patented Aug. 30, 1969 2 reticulatedfibrous webs or structures .formed of discontinuous fibers in randomdistribution.

A further purpose of this invention is to provide a method for formingfibers and reticulated webs or struc-" tures from organic solutions ofelastomeric materials.

Another object of this invention is to provide a method for theproduction of fibrous webs or structures formed of an elastomericfiber-forming material and non-adhesive preformed fibers and/or discreteparticles.

Another purpose of this invention is to provide apparatus for producingreticulated fibrous webs or structures formed of elastomeric materialswith or without non-adhesive preformed fibers and/or discrete particles.

Another object of this invention is to provide a fluidpermeable, fibrousweb or mat of elastomeric materials.

A further object of this invention is to provide a novel reticulatedfluid-permeable, fibrous Web or mat of an elastomeric fiber-formingmaterial and non-adhesive preformed fibers and/or discrete particles.

Other objects and advantages of this invention will become apparent fromthe description and claims which follow.

In the drawings,

Figure 1 is a diagrammatical, elevational view, partly in section, ofone form of apparatus for the practice of the method of this invention;

Figure 2 is a diagrammatical, elevational view, partly in section ofanother form of apparatus for the practice of the method of thisinvention;

Figure 3 is a diagrarnmatical, elevational view, partly in section, of afurther form of apparatus for the pro duction of the products of thisinvention;

Figure 4 is an elevational view, partly in section, of another form ofcollecting surface for the production of shaped bodies in accordancewith this invention;

Figure 5 is a photograph, at an enlarged scale, of a reticulated productof this invention;

Figure 6 is a schematic diagram of a production unit .for themanufacture of a laminated, reticulated product of this invention; and

Figures 7 and 8 are diagrammatical, elevational views, partly insection, illustrating further forms of collecting surfaces for theapparatus of this invention.

The present invention contemplates the production of relatively long,discontinuous, fine fibers of elastomeric materials by a sprayingtechnique wherein the fiber-forming spraying liquid is extruded into andwithin a primary or high velocity stream of gas as an initial relativelylarge-diameter stream of plastic which is attenuated and brokentransversely into a plurality of fibers or fibrils before landing on acollector. Unlike dry spinning, as performed in the rayon and syntheticfiber industries, in which a spinneret with multiple minute holes isused to produce a predetermined number of filaments each substantiallyof the same size as the holes and in which the continuous filaments arepulled continuously from the face of the spinneret to a movingcollector, the fiberforming process of the present invention utilizes asingle relatively large extrusion orifice producing a singlelargediameter plastic stream which is attenuated and broken transverselyinto a plurality of fibers, the number of which is always greater thanone and the diameters of which fibers are small fractions of the orificediameter, there being no continuous filament running between the orificeand the collector.

The velocity of the gas is appreciably higher than the velocity ofextrusion of the spraying liquid and the direction of extrusion iscoincident or concurrent with the direction of the gas flow. The highvelocity stream of gas attenuates the sprayed liquid, breaks theattenuated plastic stream transversely and partially sets theelastomeric material due to the partial evaporation of solvent to form aplurality of fibers having diameters Smaller than the orifice. Asecondary or low velocity stream of gas is provided which has a velocitylower than that of the primary stream of gas but greater-than that ofextrusion of the fiber-formingliquidv ,The secondary substitutes such aschloroprene polymers, for example,

neoprenes; butadiene-acrylonit'rile copolymers known as Buna-N, forexample, Butaprene, Paracril, Ameripol-ll, Perbunm,-Chemigurn, andHycar-OR; butadiene-styrene copolymers, for example, Ameripol-F,Hycar-OS and GPWS; 'isoprene-isobutylene ,copolymers, for example, GRIand butyl; and organic polysulfides, for example, Thiokol. be utilizedto provide desired characteristics. The specific elastomers areenumerated merely as illustrative and are not intended as limitationsofthe. invention.

The spraying or fiber-forming liquid may be formed. a by dissolving thefiber-forming elastomeric material in a satisfactory organic solventsuch as aliphatic and arematic hydrocarbons, chlorinated hydrocarbons,aralkyl hydrocarbons and the like, those beingpreferred which willvolatilize readily at moderately elevated temperatures. The solventutilized in forming the spraying liquid will be dependent upon thespecific elastomer and upon characteristics desired in the sprayingliquid such as volatility of the solvent. For example, solvents Whichare satisfactory include benzene, naphtha, toluene, xylenecyclohexanone, ethylene chloride, methylene chloride, carbontetrachloride, nitroparaflins, ketones and the like. Such inexpensivevolatile organic solvents as benzene and naphtha are entirelysatisfactory for use in fiberforming liquid containing natural rubber.The spraying liquids may contain from about 5% to about 50% *of thefiber-forming elastomeric material and preferably contain between aboutand about 35% rubber or rubber substitute.

Gas-forming or blowing agents such, for example,'as

ammonium carbonate, sodium acid carbonate, diazoamiw nobenzene the like,may be added to the elastomeric materials or spraying liquids, ifdesired. Theseagents include solids and gases and are commonly employedin" the production of sponge rubber and porous rubber sheet andproducts. .They are adapted to release or form a gas such as ammonia,carbon dioxide or other inert gas at temperatures at which theelastomeric material is cured orvulcanized. a

The properties and characteristics of the fibers formed from theelastomeric materials may be varied as desired Mixtures of specificelastomeric materials may Detackifying Carborundum, silica, etc., maybeincorporated in the spraying liquid to provide products having abrasiveprop erties. Fillers such 'as clay, whiting, kaolin, French chalk andthelike may be added to impart desired characteristics and to reduce thecost of the fibers. The amount of the additive may be varied over a widerange as desired. In the case of solid fillers, from about to about 150%filler,'such'as clay, finely divided pigments and the like, based uponthe weight of the elastomer, may be incorporated in the spraying liquid.Lesser or greater amounts, however, may be employed depending upon thetype of product desired.

The additive substances may be mixed with the elastomer as by millingthe elastomer and the additive, or the additive substance may be'mixedwith or dispersed in the solution of the elastomer; By varying theamount of solvent and the amount of additive substances and the degreeof milling, the viscosity of the spraying liquid may be varied over anextremely wide range. it is pos sible to utilize spraying liquids informing the products of this invention which are totally unsuited foruse in the usual or conventional spinning methods.

The primary gas stream may be at normal atmospheric temperatures oranyother desired temperatures. For example, the temperature maybeelevated so as to increase the rate of volatilization of the solvent.The gas may consist of'a chemically reactive gas, steam, air or otherinert gas such as nitrogen, carbon dioxide and the like. Since thefibers as they are formed by the attenuating effect of the gas streamand the volatilization of'the solvent are tacky or cementitious, solidparticles or short preformed fibers may be introduced into the primarygas stream so as to provide a coating on the ness of the fibers andallows the collection of the fibers in a body wherein there is little orno adhesion between the crossing filaments. Short, preformed fiberseither synthetic or artificial such as viscose rayonstapie, cotton,Wool, asbestos, etc., or finely divided particles such as leather, rayonflock, cork dust and the like may introduced if'desired.

Similarly, the. secondary gas stream may be at normal atmospherictemperatures or atany desired temperature and the gas may consist of. achemically reactive steam, air, orother inert gas such as nitrogen,carbon dioxide and the like. 7 a

Before curing or vulcanizing,"the freshly formed fibers ofelastomericmaterial are inherently tacky and after curing are potentiallyadhesivegthat is, they may be discrete particles are thereby broughtinto contact with the potentially adhesive, elastomeric fibers while thelatter are in atacky or cementitious condition and the Qpreformed fibersor discrete particles" adhere to the elastomeric fibers. The fibers maybe collected while the fibers are in an adhesive conditioner afterwards,

or a detackifying'substance such as talc may be introduced to counteractthetacky nature of the elastomeric may be incorporated in thespray'ingyliquidso as to. de

crease the natural adhesive or tacky nature'of'the'urrvuh canizedfibers; .Coloring agents, such as dyes and .pigr V 'ments may beutilized to'produce fibers having desired 1 colors err-tints. Abrasiveparticles such as emery dust,

'lated web or" structure.

while the fibers are in atacky condition, the fibers will fibers so thatupon collection there is little or noadhesion. The fibers as collectedare deposited in a completely random distribution or. haphazard manner.to form. a reticu- Where the .fibers are collected stick togetherwherelthey contact each other and where they contact the preformednon-elastomeric fibers. Conventional methods of handling staple fibers,even though elaborate carding equipment is employed, do not produce webshaving the totally random and haphazard fiber structure formed by thismethod. Our method also eliminates the activating procedure requiredwhere conventional methods are utilized in forming the mixed fiber orcomposite bodies.

Among the non-adhesive non-elastomeric fibers which maybe employed informing the composite bodies are natural fibers, such for example aswood or pulp fibers, cotton, fiax, jute, kapok, wool, hair and silk,other natural substances such as leather and cork; and synthetic fibers,for example, cellulosic fibers such as cellulose hydrate, cellulosederivatives such as cellulose esters, mixed cellulose esters, celluloseethers, mixedcellulose ester-ethers, mixed cellulose ethers, cellulosehydroxyalkyl ethers, cellulose carboxyalkyl ethers, cellulose etherxanthates, cellulose xantho-fatty acids, cellulose thiourethanes; fibersmade of alginic acid, gelatine, casein; mineral fibers such as spunglass, asbestos, mineral wool and the like; and fibers made of naturaland synthetic resins which are not rendered tacky when the potentiallyadhesive fibrils are rendered tacky; also fibers and filaments made byslitting, cutting or shredding nonfibrous films, such as wastecellophane.

In addition to or as a substitute for such non-elastomeric fibers,particles of various classes may be introduced through the primary orsecondary air stream, such for example as cork dust, wood flour, leatherdust, or flake particles, or fibers of floc length. Products havingabrasive properties may be formed by introducing abrasive particles suchas emery dust or larger size particles. The tackiness of the fibers maybe reduced by introducing a detackifier such as powdered talc. Two ormore difierent foreign substances may be introduced into the gas streamand the substances may be of different physical form; for example, onemay be in fiber form and the other in powdered form, depending upon thenature and characteristics desired in the final product. The gas streamsmay be air, an inert gas or a chemically reactive gas, such for exampleas nitrogen, sulfur dioxide and steam.

The present fiber-forming process may be practiced by I utilizingapparatus as illustrated more or less diagrammatically in Fig. 1. Atower 1 which may be cylindrical in form is provided with a sprayingunit 2 preferably centered within the tower. The spraying unit comprisesa conduit 3 which terminates in an upwardly extending spray tip 4 havinga suitable orifice at its upper end and a conduit 5 which terminates inan upwardly extending nozzle 6. The spray tip 4 is preferably mountedconcentrically within and it extends slightly above the nozzle 6. Thefiber-forming liquid is continuously extruded through the spray tip bymeans of a suitable pump, not shown. A stream of gas such as air iscontinuously passed through conduit 5 and nozzle 6 by suitable meanssuch' as a blower, not shown, the velocity of the gas emerging from thenozzle'being appreciably higher than the velocity of extrusion of thespraying liquid. The elastomeric composition is forced out of the tip 4as a single continuous plastic stream which is attenuated and brokentransversely into discontinuous fibers or fibrils of varying length bythe high velocity primary gas stream. The velocity of the extrusion andthe velocity of the gas may be varied so as to regulate the amount ofattenuation and hence the diameter of the fiber or fibrils, and

6 fiber or fibrils. The relative velocity of the gas How to the velocityof extrusion may be increased to provide fibrils of shorter length forthe production of lower density products. It is not necessary and inmany cases not desirable to heat the primary gas stream.

A secondary stream of gas such as air is passed upwardly through thetower 1 by means of a blower 7 and surrounds or envelops the primarystream of gas. This main column of gas is passed upwardly at a velocitylower than that of the gas which is supplied through nozzle 6. As theextruded liquid is attenuated and the velocity of the gas from nozzle 6approaches the velocity of the main stream of gas, the attenuated fibersare then carried upward by the main stream of gas. In order to increasethe drying or setting rate of the fibers, the temperature of thesecondary gas stream may be elevated above C. so that the fibers as theyreach the top of the tower 1 are in an adhesive or tacky condition, orthe conditions may be varied so that the fibers are deposited in anon-tacky condition with little or no adhesion between the fibers.

The multiplicity of fibers is carried by the secondary gas stream to asuitable collecting means at the top of the tower such as a poroussurface 8. In the preferred form, the collector is a moving endlessscreen or a porous drum. As the fibers collect and deposit on thescreen, the resistance of the collected reticulated mat 9 to the flow ofgas increases and for the production of thicker webs or mats, a suctionchest 1% may be provided above the conveyor screen. The suction chestalso may be employed to aid in the recovery of the solvent, if desired.The tendency of the air-borne attenuated fibers to contact and adhere tothe walls of the tower may be reduced by providing a conical annularring 11 in the tower positioned above the spinning tip. The velocity ofthe main column or secondary stream of gas through the tower may becontrolled to deposit the fibers on the collecting means 8 in a desiredcondition. The temperatures of the gas streams may be varied so as tocontrol the evaporation of solvent and the vulcanizing of theelastomeric material so as to deposit the fibers in a desired condition.Where the fibers are to be utilized in forming a more or less coherentreticulated mat, the temperature and velocity of the secondary gasstream are so controlled that the fibers are deposited on the conveyorscreen 8 in a somewhat adhesive or tacky, unvulcanizedcondition wherebythey become bonded together at their points of contact.

The collected web 9 may be stripped from the conveyor screen 8 andpassed through a suitable heater 12 wherein the elastomeric material isvulcanized. The reticulated web or mat 9 is then accumulated on atake-up roll or drum 13. The sheet or web is reticulate in structurehaving the fibers arranged in a completely and totally random orhaphazard order and is highly porous and penneable, as shown in Figure5.

Relatively thick bodies or structures may be produced by a laminatingtechnique. The unvulcanized, reticulated web may be strippedfrorn theconveyor screen and folded upon itself to provide the desired thickness.As alternatives, the unvulcanized web may be cut to a desired size and aplurality of such cut webs assembled, or a plurality of uncut webs ofdesired lengths may be assembled to form the desired thickness. Sincethe fibers of the unvulcanized webs are tacky and adhesive, the fiberson contiguous surfaces adhere to each other upon contact so as to bondthe adjacent layers into a unitary structure. Additional bonding betweenadjacent layers may be obtained by the application of pressure to theassembly whereby the exposed fibers lying beneath the plane of thesurface fibers of adjacent layers are brought into contact. The pressedassembly is then vulcanized so as to provide a unitary body of thedesired thickness. Such unitary body remains permeable and hassubstantially the same elasticity and strength characteristics in alldirections in the plane of the laminations.

at the top of the tower.

rable fibers which are not bonded together, then the collector is spacedfurther away from the tip or nozzle and a detackifier is incorporated inthe spraying liquid and another detackifier such as talc is blown inwith the primary or secondary gas stream. Also, the'temperature of thegas is elevated to evaporate more of the solvent from the fibers beforethey are deposited or collected.-

In the'production of fibrous webs comprising preformed non-adhesivefibers and/ or discrete particles and :the elastomeric Sprayed fibersformed as described, the pr..-

formed non-adhesive fibers and/ or discrete particles are 7 preferablyintroduced into the secondary gas stream and may be introduced throughthe blower-7; The nonadhe sive fibers or particles are -thereby carriedor blown;

into contact with the sprayed elastomericfibers while these latterfibers are in a tackyconditionand thereby become firmlyattached to thesprayed fibers, The spraying conditions are maintained so that thesprayed fibers are still in a somewhat tacky condition when they arecollected on the conveyor screen 8. The mixed web is subsequentlysubjected to treatment to cure or vulcanize the elastomeric fiberstherein.

Although the chamber or tower is shown as being provided with a sprayingunit 2 consisting of a single spray tip and nozzle, his to be understoodthat such illustration ismerely for purposes of simplifying the drawingand the foregoing discussion. 7 A plurality of spaced spray tips may bemounted within a large chamber provided with a single secondary gasblower. In a preferred embodiment of the apparatus, a plurality ofchambers are employed, each containing a number of spaced spray tips andnozzles. It is necessary to provide an appreciable spacing such as 10inches. to 12 inches between the spray tips or orifices so as to avoidcontact between the formed fibers before a majority of the solvent hasvaporized. In any case, each spray tip is provided with its separate.

primary gas nozzle surrounding it.

A product of uniform thickness over the width of the web may be producedby utilizing a tower 14 having a square or rectangular section. Aplurality of spraying units 15 are positioned in spaced relationship ator adjacent the base of the tower.

wardly projecting nozzles 19 surroundingjthe tips." A

' spraying liquid is continuously extruded through the spray tips and astream of gas is continuously passed through the nozzles.

The spun fibers. are carried by a single secondary stream of airsupplied by the blower 7 and are collected as a.

reticulated web 20 on the collecting screen 21 supported A suction.chest 22 may. be mounted above the conveyor screen 21,115 describedhereinbeforeQ The web may be stripped from the conveyor 21 a and passedthrough a'heating chamber 12 wherein the elastomer is vulcanized and theweb or sheet finally accumulated on a take-up roll 13. r

. =As'illustrated in Figure l, a laminated product may be producedbybringing together two or more webs from different chambers or'towersbetween squeeze rolls 23 and '2 4while the elastomericfibers'are tackyand adhesive.

The tacky fibers on contiguous surfaces adhere to each.

other upon contact and additionaLbondiug'of the layers Each sprayingunit comprises a spraying liquid conduit 16 provided'with a larality ofspaced, upwardly projecting spray tips 17 and a' gas conduit 18 providedwith a plurality of spaced,;up-

8 the laminate through a heating chamber 12. The laminate is finallyaccumulated upon a suitable take-up drum 13.

By the introduction of preformed fibers or discrete particles ofnon-adhesive, non-elastom eric materials into the blower 7, both of thewebs 9 and 20 will consist of composite'web'sa If. desired, 'one .of thewebs may be formed of the elastomeric material..containing desiredadditives and the other web may be a composite structure containingpreformed fibers of discrete particles. The preformed fibers orparticlesm'ay be introduced into the duct 7A 0:"73 which supplies thesecondary air stream to the respective towers in'which the compositestructure is to be formed.

If desired, Where a plurality of spraying units are positioned within .atower, all of the spraying units may be supplied with the same sprayingliquid and each nozzle may supply the primary gas 'at the same velocity.The resulting'reticulated web' thus consists of a single composition andthe fibers will be of about the same size and length. If desired,therelative velocities of extrusion of the spraying liquid and of theprimary gas stream may be varied in dilferent spraying units to .providefibers of diiferent size and length. Products containing fibersof'two ormore'different elastomers or different elastomeric compositions may beformed by supplying spraying liquids of thedifferent elastorners or ofdifferent composition to separate spraying units. Products having colorblends may be prepared by supplying.

spraying liquids containing difierent coloring agents "to separatespraying units.

Laminatedreticulated products wherein the outer plies -tained so. as-toform a reticulated web of relatively fine and short fibers. The two websare subsequently laminated and the elastomers vulcanized. By applying astencil over a first formed web a layer of the same.

or different elastomer fibers may be formed on the first web inpredeterminedareas.

7 Our method may also be practiced by passing the secondary or lowvelocity gas stream in a direction countercurrent-to the primary orhighvelocity gas stream,

as illustrated in-Figure '2.. A spraying unit 26 consisting of a. spraytip and nozzle, as described hcreinbefore, is mounted at the top oftower 25, preferably concentric with respecttothe walls of the tower.The primary or high velocity gas stream" is supplied to the nozzle bysuitable means and the sprayingliquid-is extruded through the spray'tipby suitable means,-not shown. 'The direction of travel of the primarygas stream and the direction of extrusion are downwardly. Theattenuation of the spraying solution and evaporation ofthe solvent bythe primary gas stre'amis identical to that described hereinbefore. Z vm The secondary or low velocity gas stream is passed upwardlythroughlthe tower as by'means of ablower 27. The secondary gas stream ispassed at. a velocity sufiicient to support or retard the fall ofthe'attenuated fibers so as to' deposit the fibers on the collectingscreen 28 many desired condition. The fibers maybe deposited 1n a' tackyor cementitious, unvulcanized condition to cause them to' effect animmediate bonding at 1 their points of contact. reticulate d web may'be' 7 passed through a suitable heater 2% to vefiect a curing orvuicanization of the elstonier. The cured web-is than str pped from the.conveyor as by meansofa doctor blade 39'and the vulcanized fwebcollected on a take in the production of composite sheets or webs, it isnot necessary that the preformed non-adhesive fibers or particles beintroduced with the secondary gas stream. As shown in Figure 3, thetower 32 is provided with the esired spinning unit 33 and a duct 34through which the secondary gas stream is supplied to the tower.Snitable heating means 35 may be mounted in the duct 34 so as to permita control of the temperature of the secondary gas stream. A tertiary gassupply may be introduced by positioning suitable blowers 36, preferablyabove the point at which the fibers are formed. The preformednon-adhesive fibers or particles may be introduced by means of thetertiary gas stream. For example, powdered talc may be introduced by thetertiary air stream after the fibers are formed. If desired, one type ofpreformed non-adhesive fiber or particle may be introduced by means ofthe secondary gas stream. For example, rayon staple fibers may beintroduced by means of the secondary gas stream and powdered talcintroduced in the tertiary gas stream to form a loosely bonded compositebody.

In forming the fibers, there is some tendency toward the inter-twiningor roping of the adhesive fibers as they are carried upwardly in [thegas stream. This is particularly noticeable when spinning from multiplespinning units and results in the formation of rope-like or bandlikefibrous strands as shown in Figure 5. The resulting reticulated web isthereby formed of single individual discontinuous fibers and band-likefibers formed by individual fibers bonded-together longitudinally asshown in Figure 5. There is also a tendency for some fibers to depositalong the Walls of the tower .to form a very loose and open Web in whichthe fibers are in a more orderly arrangement. This material may beemployed for some purposes or the web, since the elastomer has not beenvulcanized, may be reused in an additional batch of elastomericcomposition and used as the spraying liquid.

The fibers may be deposited on a shaped collecting surface asillustrated in Figure 4. The collector 44 of any desired shape, as forexample, a girdle shape, may be rotatably supported at the top of tower45 and provided with suitable means for rotation. The fibers are therebydeposited in the form of the desired article and a desired thickness isobtained by slowly rotating the shaped collector until a body of thedesired thickness is formed. The shaped collector is porous and ispreferably provided with a suitable conduit 46 which communicates with asuitable pump not shown to maintain a vacuum within the shapedcollector. Before the shaped web is removed from the collecting form itssurface may be flocked. It is then cured and stripped inside out to forma girdle, bathing suit or other article of wearing apparel. If desired,electrostatic means may be employed in forming the fibers and depositingfibers on such shaped collector. The fibers may be deposited directlyupon a previously shaped article, the article itself serving as thecollecting means to provide a layer of a reticulated, fibrouselastomeric web.

As explained hereinbefore, the fibers may be deposited under conditionsso as .to provide a high degree of bonding at the points of contact.Thesheet or Web as thus formed, after suitable treatment to cure orvulcanize the elastomer may be utilized in sheet form or may be securedor laminated to other materials to form a composite laminate.

If individual elastomer fibers are desired, the spinning conditions aremaintained so as to provide a sheet or web having substantially noadherence between the deposited fibers and consisting of separablefibers. After curing or vulcanization, the fibers may be separated fromthe web for use in other products such as in the manufacture of specialtypes of papers or the manufacture of textiles. The fibers may be outinto flock lengths if desired.

Figure is a photograph, at an enlarged scale, of the reticulated,fibrous web of elastomeric fibers formed as described hereinbefore. Asshown by the photograph, the fibers are in a totally and completelyrandom or haphazard arrangement and form a permeable, lacy orreticulated web. Although there is little or substantially nocoalescence of fibers, the fibers are firmly bonded together at theirpoints and areas of contact. Where the fibers came into contact witheach other longitudinally they become firmly bonded together to form abundle of fibers and the reticulated web includes such bundles as wellas individual, discontinuous fibers. In the formation of this sheet orweb, the conditions were maintained so as to deposit the fibers whilethey were in a tacky or cementitious condition. The thickness of thesheets or webs may be regulated by controlling the speed of the conveyoror collector surface where such collector consists of an endless belt asshown in Figures 1 and 2, or, in the case of a rotating shaped collectoras shown in Figure 4, the thickness of the deposited web is controlledby the speed of rotation of the mold and by the number of revolutionsduring the deposition operation.

In Figure 6 there is illustrated schematically and in flow diagramfashion, a method for commercially producing a laminated reticulatedfibrous web in accordance with this invention. The elastomeric materialand the desired additives such as fillers, vulcanizing agents, accelerators, anti-oxidants and the like are thoroughly mixed in a conventionaltype rubber mill 50. After the required milling period, the elastomericcomposition is transferred to a conventional jacketed rubber mixer 52and dissolved in the solvent, supplied from a suitable tank 51, to formthe spraying liquid. The spraying liquid is then transferred to asuitable storage tank 53 from which it passes to a pump 54. A straineror filter 55 may be interposed between the storage tank and the pump.From the pump 54, the spraying liquid passes to the spray tips 56mounted in adjacent towers 58. The primary gas stream is supplied to thenozzles 57 by means of a blower 59. The secondary gas streams aresupplied to the bottom of towers 58 by means of a blower 60. Thespraying liquid is attenuated and the discontinuous elastomeric fibersare formed in the towers as described hereinbefore.

The fibers are collected on endless conveyor screens 61 which aredisposed at the top of the towers and the vaporized solvent and gasessupplied to the towers are removed through suction chests 61. Thereticulate webs are stripped from the collector screens 60 and arebrought together under pressure between squeeze rolls 62. The laminatedsheet may then be passed through a dusting chamber 63 wherein a detackiier such as talc is applied to the outer surfaces to reduce thetackiness of the surfaces. The sheet then may be passed between anotherpair of rolls 64 from which it is passed through a pro-curing orpre-vulcanizing chamber 65. The sheet is then passed over steam heatedrolls 66 in a curing chamber 67 to efiect a final curing orvulcanization of the elastomeric material. The cured or vulcanized sheetmay then be passed through a suitable trimming device 68 to cut thesheet to a desired width. The finished sheet is then dusted with tale ina dusting chamber 69 and collected on a suitable wind-up roll 70.

The fibrous, reticulated web or mat of elastomeric material has much thesame feel as foam and sponge rubber. However, because of the completelyrandom or haphazard arrangement of the fibers and due to the fibrousstructure of these webs or mats as compared to the cellular structure offoam and sponge rubber, the permeability of the mats is substantiallygreater per unit of thickness than foam and sponge rubber. The tearstrength and tensile strength of the webs and mats are alsosubstantially greater per unit of thickness than foam and sponge rubberalthough the permeability is greater.

It is well known that calendered rubber exhibits an appreciablydifierent elasticity and strength in the direction of calenderingascompared to the elasticity and strength 1 l in a direction transverse tothe direction of calendering. It is also well known that fibrousproducts wherein the fibers andfilaments are more or'less orientedexhibit different elasticities and strengths in the direction oforientation and in a direction transverse to the directionoforientation. The products of this invention possess su bstantially thesame elasticity and strength characterlstics in all directions in theplane of the sheet or web. It 18 also well known that upon puncturingrubber sheet, foam Elastic fabrics are very costly compared to thesheets.

and mats of'this invention because in the manufacture of such fabrics itis customary to first form a rubber thread or filament, combinethefilament with a non-elastic thread and finally weave or knit thefabric. Such woven or suit elastic fabric may have elasticity in twodirections, only if the elastic thread has been used for both the warpand the weft or filling. The reticulated Webs of this invention aresubstantially lower in cost and have a substantially uniform elasticityin not only two directions, but in all directions in the plane of theweb or mat.

Because of their high porosity and permeability, the webs and mats ofthis invention are particularly well suited for uses wherein thematerialcontacts the human ings, elastic stockings, bathing suits, foundationgarments such as girdles, belts,'garters, galluses, shoe parts suchasinner soles, and the like. The webs are also highly satisunique in thefield of elas-tomeric sheets in this respect and a V V Paraflin waxfactory for other purposes such as gas filters, thermal in selected toprovide the required resistance to oils, greases,

solvents, heat, light, abrasion and other conditions of use. in a smallscale'production of the fibrous reticulated .mats or webs of thisinvention, a tower may be employed having a diameter of four feet andaheight of fifteen feet. The spraying unit'is mounted concentricallywithin the tower at a point from about lO feet to 12 feet from th'e topof the tower, the spray tip and nozzle being directed upwardly; Aplurality of spraying units may be employed, if desired. 'A blower isprovided to introduce an inert gas such as air at the bottom of thetower and suitable heating means may be provided to permit regulation ofthe temperature of this secondary air stream. 'The collecting conveyormounted at the top or" the towermay consist of a suitable screen such asa screen formed of Saran. The spraying orifice for the elastomers may'bevaried. A'diamete'r'of 0.0-4- to 0.06

inch has been found very satisfactory for the production of fibrousreticulated webs from the elastomers. The

' primary gas stream may be provided through a'nozzle having an internaldiameter of from'about 0.5 inch to about 0.75 inch. The externaldiameter or" the spray tip may be "about 0.15 inch to about 0.2 inch andthe tube may extend from the nozzle toposition the orifice about-%'inchfrom the "nozzle. The t'ruclrne's's of the filamentary web or mat 'iscontrolled by regulating the speed ofthef collecting conveyor. i

The following "specific examples are set forth herein toillustratesthellpro'duction of fibrous reticulated webs formed ofnatural and synthetic rubbers. The tower dimensions were as set forthabove. The 'outside diameter of the spray tip was 0.165 inch and theinside diameter oft he nozzle was 0.493 inch.

Example 1 A rubber mix was prepared containing a commercialanti-oxidant, namely, AgeRite White, and a commercial accelerator,namely, Tepidone, the mix having the following compositions: l a

Parts by weight Pale crepe Zinc oxide I 5 Lime i AgeRite white Sulfur 2.Stearic acid Tepidone 2.

7 Added just before spinning.

The forego ng materials were thoroughly mixed by milling and a sprayingliquid or solution was formed containing 18.7% of the rubber compositionin a solvent consisting of 98 parts of benzene to 2 parts of ethylalcohol. The apparent viscosity lot this solution as measured by theshearing disc viscosimeter was 1 0,000 cps. The spraying solution wasextruded through an orifice having a diameter of 0.042 inch at a uniformrate of 24 cc. per minute or at a velocity of about 88 feet per minnute.The. primary air streain was supplied to the nozzle at the rate of 48c.f.m. or at a velocity of about 40,800 feet per minute. The secondaryair stream was passed through the tower at. the rateof 8,550 c.f.m. orat a velocityof about 680 feet .per minute and at a temperature of about40 C; The paraffin wax and stearic acid incorporated in the sprayingliquid serve as detackifiers' and, in additionfa small amount of talcwas introduced into the secondary air stream periodically to reducetheta'cky nature or the fibers as'they were deposited. The fibrousreticulated mat was cured after removal from the collector screen. Thepresence of the small amounts of these detackifiers permits theproduction of a loose, openweb, however, the rubber fibers were firmlybonded together at their'points of contact.

The web so formed, had much the same feel as sponge rubber but ditferedtherefrom in having a uniform elasticity and strength in all directionsin the plane of the Web. It had the appearance of a closely matted massof fine long fibers in a completely random arrangement with ExampleZ VThe same rubber composition as employed in Exampl'e 1 wasialso dissolvedin 'a naphtha base solventhaving a boiling range of 140 to 250 F,namely, a solvent'consisting of 95 parts of Amsco rubberisolvent and 5parts of alcohol, to form a'ispraying'liquid containing 27% of therubber composition. Theapparent"viscosityaof the solution was 14,000cps. The liquid was extruded at the rate of from 30 to 51 cc. per minuteorat a'velocity of from about to 187 feet per minute. The primary streamwas supplied to the nozzle at the 'rate .of 40 c.f.m. or at a velocityof about 34,000 feet per minute. The secondary air stream was passedthrough the tower at the rate of 3,000 c.flm.'or at a velocity o f'about 240 feet per minute and at a temperature of about 29 C. An

additional detackifier consisting of finely divided starch wasintroduced into the secondary air stream'periodicaliy.

The cured mat difiered from the mat as prepared in Example '1 in'thatthe fiberswere somewhatcoarser. in other respects, the mat prepared wassimilar to that .pre-

pared in Example 1.

13 Example 3 A rubber mix was prepared containing the rubber substitute,neoprene, having the following composition:

Parts by weight Neoprene Gn-M-2 (Du Pont) 300 Zinc oxide 15 AgeRitestalite 6 Stearic acid 1.5

A spraying liquid was formed consisting of 10% of the compositiondissolved or suspended in benzene. The apparent viscosity of thesolution was 4,100 cps. The liquid was extruded at the rate of 30 cc.per minute or at a velocity of about 110 feet per minute. The primaryair stream was suppiied to the spraying nozzle at the rate of 36 c.f.m.or at a velocity of about 30,600 feet per minute. The secondary airstream was passed through the tower at the rate of 8,500 c.f.m. or at avelocity of about 680 feet per minute and at a temperature of about 30C.

The reticulated webs and mats formed from this composition resemblethose prepared from the natural rubber compositions differing therefromonly in having a lower strength.

The following examples illustrate the preparation of webs or mats from arubber composition containing about 100% filler based upon the weightor" the elastomer:

Example 4 A rubber composition was prepared containing whiting, Titanoxand McNamee clay as fillers and the commercial accelerators Ethyl Tuads,captax and butyl eight.

A spraying liquid was formed containing 40% of the rubber composition inAmsco rubber solvent. The apparent viscosity of the solution was 7400cps.- The spraying liquid was extruded through an orifice having adiameter of 0.060 inch at a rate of 31.5 cc. per minute or at a velocityof about 57 feet per minute. The primary air stream was supplied to thenozzle at the rate of 35 to 45 c.f.m. or at a velocity of about 29,700feet per minute. The secondary air stream was passed through the towerat the rate of about 6,430 c.f.m. or at a velocity of about 500 feet perminute and at a temperature of about 66 C. The reticulated mat wasremoved from the collector screen and the rubber vulcanized by heatingto 100 C. for about 1 hour. Further portions of the uncured mat uponremoval from the collector screen were stacked and pressure applied tobring the adjacent surfaces into firm contact with each other. Thelaminated pad was then vulcanized by heating to 100 C. for about 1 hour.

The reticulated mat and pad was light in color and had the appearance ofa closely matted mass of fine and coarse fibers which were firmly bondedtogether at their points of contact. The mat and pad was Very porous andpossessed a very high permeability. The products had much the same feelas sponge or foam rubber but were substantially more firm. Upon flexingor bending a corner of the mat or pad and releasing the force, thecorner portion returns to its original position with a much more briskaction or snap than a sponge or foam rubber mat or pad of the samethickness. The products had substantially uniform elasticity in alldirec- 14 tions in the plane of the mat or laminations and had a hightear strength.

Example 5 A spraying liquid was prepared consisting of 40% of a rubbermix in Amsco rubber solvent, the composition consisting of The apparentviscosity of the solution was 2600 cps.

For the preparation of products from this spraying liquid, four sprayingunits were mounted in the tower at a position about '10 feet from thetop of the tower, the units being spaced from each other about 10 incheson a circle concentric with respect to the axis of the tower. Each spraytip was provided with an orifice 0.060 inch in diameter.

The spraying liquid was extruded through each orifice at a rate of about30 cc. per minute or at a velocity of about 54 feet per minute. Theprimary air stream was supplied to each nozzle at the rate of 25 c.f.m.or at a velocity of about 21,200 feet per minute. The secondary airstream was passed through the tower at a rate of about 6,430 c.f.m. orat a velocity of about 500 feet per minute and at a temperature of about55 C. The reticulated mat was removed from the collector screen and therubber vulcanized by heating to 100 C. for about 1 hour. A laminatedproduct was also prepared by assembling laminations before vulcanizing.

The reticulated mat and pad resembled those of Example 4, however, theproducts appeared more lacy and open than those of Example 4.

Although the reticulated webs and mats as formed may be employed formany uses, for many other purposes, it is desirable to incorporate. inthe mat nonadhesive preformed fibers and/or discrete particles. Thenon-adhesive fibers or discrete particles may be introduced into thesecondary air stream through the blower 7 and are carried into contactwith the elastomeric fibers as they are formed and while they are in atacky condition. Forexample a M; inch rayon staple fiber or cottonstaple and/or cork or leather dust may be introduced into the air streamin the blower. The individual preformed fibers or particles as theycontact the undried and tacky fibers adhere to the fibers, and thefibers and attached non-adhesive fibers or particles are deposited onthe collecting means in a completely random or haphazard arrangement.The presence of the preformed fibers and elastomeric adhesive fibersproduces a porous, highly permeable web which has a low elasticity orsubstantially no elasticity depending upon the relative amounts of theelastomeric fibers and preformed fibers. This type of product is welladapted for use as conveyor'belting, surgical dressings and the like andthey properties may be varied by altering the proportions of preformedfiber or discrete particles introduced into the product. I

. The elastomeric fibers may constitute from about 10% to about of thecomposite material depending upon the characteristics desired.

In the manufacture of elastic fabrics, as for use in the manufacture offoundation garments, galluses, garters and the like, one or bothsurfaces of the reticulated fibrous, elastomeric Web may be providedwith a suedelike finish. Such velvety finish may be obtained by theapplication of a suitable flock such as a rayon flock to the surface orsurfaces, as described and claimed in the copending application ofLaurence R. B. Hervey, Serial No. 400,360, filedDecernber 24, 1953,

suitable cement may be applied before application of the flock and theelastomer vulcanized following the application of the flock.

In the manufacture of foundation garments and the like in which rubbersheeting has been combined with a woven or knitted textile, it has beennecessary to perforate the rubber sheet to obtain the necessary airpermeability. The perforations generally have been provided afterassembling the rubber and textile to form the composite sheet."Subsequeiitl'y,"it has "been "necessary to treat the composite sheetbecause of the damage to the knitted textile caused by" the perforatingoperation. The use of the reticulated, fibrous elastor'neric mats orwebs of this invention'obviatesthe necessity 'of'the perforatingtreatments because the webs are-permeable and porous. The reticulate webmay be bonded or secured to the knitted or Woven textile.

, Crinkled rubber sheet is very desirable for the manufacture of sucharticles as bathing garments, for example, bathing suits,'caps, shoesand the like, because it is light in Weight, does not stretch when wet,conforms closely to the body contours and dries quickly. Howevensuchsheet is easily punctured and when punctured the sheet is It isnecessary therefore, to reinforce very readily torn. the sheet with aknitted or woven fabric which is stretch able in all directions. Theresulting material is highly objectionable because it is substantiallyimpervious and will not permit the passage of perspiration. Thereticulated, fibrous, elastomeric web of the present invention whilepossessing substantially all of the desirable characteristics of thin,crinkled rubber sheet, possesses the decided advantage that, it issufficiently permeable Y to permit the passage of perspiration andbecause 'of its fibrous structure does not tear or rip readily when punctured Material, highly satisfactory for bathing suits and the like maybe prepared by securing thin fibrous, elastomeric webs to a woven orknitted fabric which is stretchable in all directions, as described andclaimed in V the copending application of Worth Wade and; Ralph Winters,In, Serial No. 400,172, filed December 24, 1953;

If desired, one or both surfaces of the 'composite sheet material'may beprovided with flocked fibers'such asposite bodies will possess thedesirable resilient characteristics of spongeor foam rubber but, becauseof the permeability and porosity of the elastomeric web, 'will besuperior' to foam rubber in that the fibrous, reticulated Web issufiiciently porous and permeable to permit the passage of perspiration.

The elastomeric web or mat, either a single ply or a laminated bodyasdescribed hereinbefore, may be secured to thejfibrous mat=while theelastomeric web is tacky and before the elastomer has been vulcanized orthe surface of'the elastomeric webmay be'rendered adhesive or tacky bytreatment a with a solvent and the reticulated web and the fibrous matbrought: into contact and the solvent evaporated.

The'fibrous, elastomeric web may be employed alsoin forming-compositebodies consisting of at least one layer of'the reticulate web bonded toother types of non-fibrous flexible sheet materials or .to rigidsubstantially nonporous materials.

Since; variations and modifications may be made in carrying out theinvention, without departing from its spirit and scope, it is to beunderstood that the invention is not to be limited except asdefinied inthe appended claims.

'Forexampl e, although Figures'l, Zand illustrate a The flock may beapplied while the surface ofthe web is tacky ora single collectingscreen positioned at substantially right angles to the axis of thetower, the collecting screen may be mounted at any other desired angle.If desired, a plurality of collecting screens may be provided asillustrated in Figures 7'and 8. In the modification shown in Figure 7,the tower 71 is provided'with two inclined collecting screens 72; Thesupporting rolls 73 are so positioned as to serve as squeeze rollsbetween which the webs deposited on each of the collectors are broughttogether to form a laminated, reticulated web 74. As shown in Figure8,.the removal of the loose, open web formed by the deposition of somefibrils on the walls of the tower 75, as described hereinbefore, maybefacilitated by collector belts or screens 76 and '77 which maycomprise a par. or all of the walls of the tower. which are notdeposited on the collecting screen 78 may thereby be collected on thebelts 76 and 77 and may be continuously removed. Further modificationswill be apparent to those skilled in the art.

We claim:

1. The method ofproducing an elastic, reticulated, fibrous shot-freebody which comprises providing'a fiberforming liquid containing afiber-forming elastomeric .material; establishing a high velocity streamof gasydischarging the stream of gas into the ambient atmosphere;extruding the fiber-forming liquid into and within the V stream of gasat a point beyond the point of discharge of the stream of gas, thedirection of extrusion being coincident with the direction of the gasflow; attenuating the extruded fiber-forming liquid, breaking theattenuated fiberforming liquid into discontinuous lengths and .at leastpartially setting the attenuated fiber-forming liquid to formdiscontinuous fibers substantially free of shotby m'aintaininglthevelocityof the stream of gas at the point of. discharge at a valuegreater than the velocity of ex trusion of ,thefiber-forming liquid; andcollecting the discontinuous fibers in random distribution toform areticulated; sheet-like, fibrous shot-freebody.

'2. The. .method as defined. in claim 1, wherein the.

. fiber-forming liquid comprises a solution of natural rub truding thefiber-f orming liquid into and within the primary stream of gas at apoint beyond the point of discharge of the stream of gas/the directionof extrusion being coincident with the direction of the gas flow;attenuating the extruded fiber-forming liquid, breaking the attenuatedfiber-forming liquid into discontinuous lengths velocity of extrusion ofthe fiber-forming liquid; andsuspending the fibers, completing thesetting. thereof and depositing the fibers in random distribution toform a reticulated, sheet like, fibrous shot-free body bypassing theambient atmosphereupwardly at a velocity greater than the velocityofextrusion of the fiber-forming liquid but lower than the velocity of theprimary stream of gas. 5. The method of producing an elastic,reticulated,

fibrous shot-free bodywhich comprises providing a fiber-forming liquidcontaining a fiber-forming elastomeric material; establishing a primarystream of gas;

discharging the primary stream of gas upwardlyinto the ambientatmosphere; extruding the fiber-forming liquid upwardly into and Withinthe primary stream of gas at apoint beyond the pointof discharge of thestream of gas, the direction of extrusion being coincident with thedirection of the gas flow; attenuating the extruded fiber- The fibersforming liquid, breaking the attenuated fiber-forming liquid intodiscontinuous lengths and at least partially setting the attenuatedfiber-forming liquid to form discontinuous fibers substantially free ofshot by maintaining the velocity of the primary stream of gas at thepoint of discharge at a value greater than the velocity of extrusion ofthe fiber-forming liquid; and suspending the fibers, completing thesetting thereof and depositing the fibers in random distribution to forma reticulated, sheetlike, fibrous shot-free body by passing the ambientatmosphere upwardly at a velocity greater than the velocity of extrusionof the fiber-forming liquid but lower than the velocity of the primarystream of gas.

6. The method of producing an elastic, reticulated, fibrous shot-freebody which comprises providing a fiberforming liquid containing afiber-forming elastomeric material; establishing a primary stream ofgas; discharging the stream of gas into the ambient atmosphere;extruding the fiber-forming liquid into and within the primary stream ofgas at a point beyond the point of discharge of the stream of gas, thedirection of extrusion being coincident with the direction of the gasflow; attenuating the extruded fiber-forming liquid, breaking theattenuated fiber-forming liquid into discontinuous lengths and at leastpartially setting the attenuated fiber-forming liquid to formdiscontinuous fibers substantially free of shot by maintaining thevelocity of the primary stream of gas at the point of discharge at avalue greater than the velocity of extrusion of the fiber-formingliquid; suspending the fibers, completing the setting thereof anddepositing the dried fibers in random distribution to form areticulated, sheet-like, fibrous shot-free body by passing the ambientatmosphere upwardly at a velocity greater than the velocity of extrusionof the fiber-forming liquid but lower than the velocity of the primarystream of gas; laminating the sheet-like body before the elastomericmaterial has been cured; and curingthe elastomeric material to form aunitary, elastic, reticulated, fibrous body.

7. The method of producing an elastic, reticulated, fibrous shot-freebody which comprises forming a fiberforming liquid containing afiber-forming elastomeric material; establishing a primary stream ofgas; discharging the primary stream of gas upwardly into the ambientatmosphere in each of a plurality of chambers; extruding a fiber-formingliquid upwardly into each of the primary streams of gas at a pointbeyond the point of discharge of the stream of gas, the direction ofextrusion being coincident with the direction of the gas flow;attenuating the extruded fiber-forming liquid, breaking the attenuatedfiber-forming liquid into discontinuous lengths and at least partiallysetting the attenuated fiberforming liquid to form discontinuous fiberssubstantially free of shot by maintaining the velocity of each of theprimary streams of gas at the point of discharge at values greater thanthe velocity of extrusion of the respective fiber-forming liquid;suspending the fibers, completing the setting thereof and depositing thefibers in random distribution to form a reticulated, sheet-like, fibrousshot-free web in each of the chambers by passing the ambient atmosphereupwardly in each of the chambers at a velocity greater than the velocityof extrusion of the fiber-forming liquid but lower than the velocity ofthe respective primary stream of gas; bringing the sheetlike,fibrouswebs together under pressure before the elastomeric material hasbeen cured; and curing the elastomeric material to form a unitary,elastic, reticulated fibrous body.

8. The method of producing a reticulated, fibrous body which comprisesforming a fiber-forming liquid containing a fiber-forming elastomericmaterial; establishing a primary stream of gas; discharging the primarystream of gas upwardly into the ambient atmosphere; extruding thefiber-forming liquid upwardly into and within the primary stream of gasat a point beyond the point of discharge of the stream of gas, thedirection of extrusion being coincident with the direction of the gasflow; attenuating the extruded fiber-forming liquid, breaking theattenuated fiber-forming liquid into discontinuous lengths and at leastpartially setting the fiber-forming liquid to form discontinuous fiberssubstantially free of shot by maintaining the velocity of the primarystream of gas at the point of discharge at a value greater than thevelocity of extrusion of the fiber-forming liquid; passing the ambientatmosphere upwardly; introducing particulate, non-adhesive material intoat least one of the streams of gas, the particulate, non-adhesivematerial being selected from the group consisting of preformed,non-adhesive fibers, preformed, non-adhesive, discrete particles andmixtures thereof; and suspending the fibers and the particulatenon-adhesive material, completing the setting of the fibers anddepositing the fibers and the particulate, non-adhesive material inrandom distribution to form a reticulated, sheet-like fibrous body bymaintaining the velocity of the ambient atmosphere greater than thevelocity of extrusion of the fiber-forming liquid but lower than thevelocity of the primary stream of gas.

9. The method as defined in claim 8, wherein the particulatenon-adhesive material is introduced into the ambient atmosphere.

10. Apparatus for the production of permeable, elastic, reticulated,fibrous shot-free bodies of elastomeric materials which comprises atower, a spraying unit positioned within the tower including an upwardlyprojecting nozzle for passing a primary stream of gas at a high velocitythrough the tower and an upwardly projecting spraying tube extendingthrough the nozzle and having an extrusion orifice positioned beyond theend of the nozzle and in the path of the high Velocity stream of gas forextruding a spraying liquid containing an elastomeric fiber-formingmaterial into and within the primary stream of gas at a point beyond theend of the nozzle thereby attenuating the extruded liquid and breakingthe extruded liquid into discontinuous shot-free fibers, means forpassing the ambient atmosphere in the tower upwardly at a low velocitythrough the tower to carry the fibers upwardly and means including anendless conveyor positioned at the top of the tower for collecting thefibers.

References Cited in the file of this patent UNITED STATES PATENTS I468,216 Birge Feb. 2, 1892 1,979,251 Chapline Nov. 6, 1934 2,152,901Manning Apr. 4, 193.9 2,411,660 Manning Nov. 26, 1946 2,476,283Castellan July 19, 1949 2,586,275 Toulmin Feb. 19, 1952 FOREIGN PATENTS804,987 France Aug. 17, 1936

